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35
Sep 19, 2013
09/13
by
A. Goldwurm
texts
eye 35
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The Center of our Galaxy is a peculiar region where a number of crucial astrophysical phenomena take place, from star formation to SN explosions and accretion onto a massive black hole. The quest for a massive black hole in the Galactic Nucleus is of course of particular relevance because, it would be the closest of such extreme objects, which are now believed to reside in most of the galactic nuclei of the universe. I will review here the main observational characteristics of the Galactic...
Source: http://arxiv.org/abs/astro-ph/0102382v1
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45
Sep 23, 2013
09/13
by
A. Goldwurm
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eye 45
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I present here a review on the high energy phenomena occurring in the Galactic Center region, and report in particular on the results obtained from recent X-ray and gamma-ray observations.
Source: http://arxiv.org/abs/astro-ph/0511221v1
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97
Jul 20, 2013
07/13
by
Andrea Goldwurm
texts
eye 97
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The Galactic Center is a prominent source in X-rays and gamma-rays and the study of its high-energy emission is crucial in understanding the physical phenomena taking place in its dense and extreme environment, phenomena that are possibly common to other galactic nuclei. However this emission is also very complex and consists of both thermal and non thermal radiation produced by compact and extended sources, surrounded by more diffuse components. In spite of the fundamental advances obtained in...
Source: http://arxiv.org/abs/1007.4174v1
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34
Sep 18, 2013
09/13
by
A. Goldwurm
texts
eye 34
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In the last decade our knowledge on galactic black hole systems and in particular on their high energy behavior has considerably improved. I will briefly review here the main results obtained by the high-energy missions SIGMA/GRANAT, Compton-GRO, Beppo-SAX and Rossi-XTE, on these objects and, in particular, I will discuss the spectral shapes observed at energies higher than 30 keV and the detections of high energy features at > 300 keV. Galactic black holes are indeed main targets for the...
Source: http://arxiv.org/abs/astro-ph/0212502v1
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43
Sep 23, 2013
09/13
by
Fulvio Melia; Maurizio Falanga; Andrea Goldwurm
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eye 43
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The Galaxy's supermassive black hole, Sgr A*, produces an outburst of infrared radiation about once every 6 hours, sometimes accompanied by an even more energetic flurry of X-rays. The NIR photons are produced by nonthermal synchrotron processes, but we still don't completely understand where or why these flares originate, nor exactly how the X-rays are emitted. The power-law electrons radiating the infrared light may be partially cooled, so the distribution may be a broken power law with a...
Source: http://arxiv.org/abs/1109.6736v1
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5.0
Jun 29, 2018
06/18
by
Michael Walls; Maria Chernyakova; Regis Terrier; Andrea Goldwurm
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eye 5
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In the centre of our galaxy lies a super-massive black hole, identified with the radio source Sagittarius A*. This black hole has an estimated mass of around 4 million solar masses. Although Sagittarius A* is quite dim in terms of total radiated energy, having a luminosity that is a factor of $10^{10}$ lower than its Eddington luminosity, there is now compelling evidence that this source was far brighter in the past. Evidence derived from the detection of reflected X-ray emission from the giant...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1609.00175
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Kirchen Calender : inwelchemnach, Ordnung gemeyner Allmanach, die Monat, Tag, vnd die fürnembsten Fest des ganzen Jars, mit irem Gebrauch : auch der heyligen Apostel, vnd Christlichen Bischoff, Leerer, vnd Martyrer, Glaub, Leben, vnd bestendige Bekandtnuss ... kürtzlich verfasset, vnd mit vilen schönen Figurn, vber vorige Edition, gezieret vnnd gemehret : allen Christen sehr tröstlich vnnd nützlich zuwissen
Sep 23, 2016
09/16
by
Goldwurm, Caspar; Weiditz, Hans, approximately 1495-approximately 1536
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eye 261
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Binding: vellum, perhaps ca. 1700 (to judge from the dates of inscriptions on the endpapers). Author, brief title and date written at head of spine. Foredges turned down over text block. Page edges blue
Topic: Church calendar
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35
Sep 22, 2013
09/13
by
P. Goldoni; S. Chaty; A. Goldwurm; A. Coleiro
texts
eye 35
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X-shooter is a second generation ESO-VLT instrument that had its first light in October 2009. It is a single object medium-resolution spectrograph whose main feature is the capability of covering simultaneously in a single observation the range from 3000 to 24000 Angstrom. This unique capability is very well suited to investigate the complex spectra of the optical counterparts of X/gamma ray sources which usually display signatures of different components in emission and absorption. In July...
Source: http://arxiv.org/abs/1302.0714v1
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44
Sep 19, 2013
09/13
by
P. Goldoni; A. Goldwurm; P. Laurent; F. Lebrun
texts
eye 44
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The Imager on Board Integral Satellite (IBIS) is the imaging instrument of the INTEGRAL satellite, the hard-X/soft-gamma ray ESA mission to be launched in 2001. It provides diagnostic capabilities of fine imaging (12' FWHM), source identification and spectral sensitivity to both continuum and broad lines over a broad (15 keV--10 MeV) energy range. It has a continuum sensitivity of 2~10^{-7} ph cm^{-2} s^{-1} at 1 MeV for a 10^6 seconds observation and a spectral resolution better than 7 % at...
Source: http://arxiv.org/abs/astro-ph/9709096v1
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59
Sep 18, 2013
09/13
by
John A. Tomsick; Stephane Corbel; Andrea Goldwurm; Philip Kaaret
texts
eye 59
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The black hole candidate (BHC) X-ray transient 4U 1630-47 continuously produced strong X-ray emission for over 2 years during 2002-2004. We use observations made with the Rossi X-ray Timing Explorer (RXTE) to study the source throughout the outburst along with hard X-ray images from the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL). The source exhibits extreme behaviors, including measured inner disk temperatures (Tin) between 2.7 and 3.8 keV, which are only rivaled by the...
Source: http://arxiv.org/abs/astro-ph/0505271v1
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46
Jul 20, 2013
07/13
by
P. Laurent; P. Goldoni; A. Goldwurm; F. Lebrun
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eye 46
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The Imager on Board the Integral Satellite (IBIS) is one of the two main telescopes of Integral, the ESA soft gamma-ray mission to be launched in 2002. The Integral Core Program will be divided into two main parts, the Galactic Centre Deep Exposure program and the Galactic Plane Scan for a total amount of around 6 .6 10^6 seconds each year. In this paper, we will study the visibility of persist ent galactic black holes as observed by IBIS during these two phases of the Core Program. We will...
Source: http://arxiv.org/abs/astro-ph/0107581v1
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52
Sep 22, 2013
09/13
by
Gabriele Ponti; Mark R. Morris; Regis Terrier; Andrea Goldwurm
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eye 52
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The Milky Way centre hosts a supermassive Black Hole (BH) with a mass of ~4*10^6 M_Sun. Sgr A*, its electromagnetic counterpart, currently appears as an extremely weak source with a luminosity L~10^-9 L_Edd. The lowest known Eddington ratio BH. However, it was not always so; traces of "glorious" active periods can be found in the surrounding medium. We review here our current view of the X-ray emission from the Galactic Center (GC) and its environment, and the expected signatures...
Source: http://arxiv.org/abs/1210.3034v1
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36
Sep 23, 2013
09/13
by
A. Goldwurm; P. Goldoni; P. Laurent; F. Lebrun; J. Paul
texts
eye 36
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In spite of increasing evidences of the presence of a massive Black Hole at the Galactic Center, its radio counterpart, Sgr A*, shows little activity at high energies, and recent models involving energy advection (ADAF) have been proposed to explain this difficulty. We present results on the hard X-ray emission from the galactic central square degree obtained from the SIGMA/GRANAT 1990-1997 survey of this region. The best upper limits available today on the Sgr A* 30-300 keV emission are...
Source: http://arxiv.org/abs/astro-ph/9904104v1
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57
Jul 20, 2013
07/13
by
M. Falanga; F. Melia; M. Prescher; G. Belanger; A. Goldwurm
texts
eye 57
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Sgr A* is thought to be the radiative manifestation of a ~3.6E6 Msun supermassive black hole at the Galactic center. Its mm/sub-mm spectrum and its flare emission at IR and X-ray wavelengths may be produced within the inner ten Schwarzschild radii of a hot, magnetized Keplerian flow. The lightcurve produced in this region may exhibit quasi-periodic variability. We present ray-tracing simulations to determine the general-relativistically modulated X-ray luminosity expected from plasma coupled...
Source: http://arxiv.org/abs/0804.2855v1
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71
Sep 17, 2013
09/13
by
Gabriele Ponti; Regis Terrier; Andrea Goldwurm; Guillaume Belanger; Guillaume Trap
texts
eye 71
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We present the result of a study of the X-ray emission from the Galactic Centre (GC) Molecular Clouds (MC) within 15 arcmin from Sgr A*. We use XMM-Newton data (about 1.2 Ms of observation time) spanning about 8 years. The MC spectra show all the features characteristic of reflection: i) intense Fe Kalpha, with EW of about 0.7-1 keV, and the associated Kbeta line; ii) flat power law continuum and iii) a significant Fe K edge (tau~0.1-0.3). The diffuse low ionisation Fe K emission follows the MC...
Source: http://arxiv.org/abs/1003.2001v1
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46
Sep 22, 2013
09/13
by
Gabriele Ponti; Regis Terrier; Andrea Goldwurm; Guillaume Belanger; Guillaume Trap
texts
eye 46
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We present the result of a study of the X-ray emission from the Galactic Centre Molecular Clouds (MC), within 15 arcmin from Sgr A*. We use XMM-Newton data spanning about 8 years. We observe an apparent super-luminal motion of a light front illuminating a MC. This might be due to a source outside the MC (such as Sgr A* or a bright and long outburst of a X-ray binary), while it can not be due to low energy cosmic rays or a source located inside the cloud. We also observe a decrease of the X-ray...
Source: http://arxiv.org/abs/1004.1412v1
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47
Sep 19, 2013
09/13
by
P. Goldoni; A. Goldwurm; P. Laurent; F. Lebrun; B. Cordier
texts
eye 47
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We simulate the observation of a bright Nova Musca-like X-ray nova during outburst with INTEGRAL, the next ESA gamma-ray space observatory. We will show how performances of the INTEGRAL instruments allow deep study of X-ray Novae and will evaluate the scientific output that INTEGRAL will provide on this class of transient gamma-ray sources, which are now believed to contain black holes in low mass binary systems. The variable high-energy feature around 511 keV observed from X-ray Nova Musca in...
Source: http://arxiv.org/abs/astro-ph/0102362v1
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43
Sep 22, 2013
09/13
by
P. Goldoni; J. -M. Bonnet-Bidaud; M. Falanga; A. Goldwurm
texts
eye 43
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We report on preliminary results of IBIS/ISGRI serendipitous observations of Cygnus X-3 in the 15-100 keV energy range during the INTEGRAL Performance and Verification phase. This peculiar microquasar was inside IBIS/ISGRI field of view at a ~ 9 degrees distance from the pointing direction during Cygnus X-1 staring observations in November and December 2002. We analyzed observations from 27 November 2002 to 8 December 2002 with an effective on source exposure time of ~ 300 kiloseconds. Cyg X-3...
Source: http://arxiv.org/abs/astro-ph/0310156v1
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52
Sep 18, 2013
09/13
by
Maurizio Falanga; Fulvio Melia; Michel Tagger; Andrea Goldwurm; Guillaume Belanger
texts
eye 52
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Near-IR and X-ray flares have been detected from the supermassive black hole Sgr A* at the center of our Galaxy with a (quasi)-period of ~17-20 minutes, suggesting an emission region only a few Schwarzschild radii above the event horizon. The latest X-ray flare, detected with XMM-Newton, is notable for its detailed lightcurve, yielding not only the highest quality period thus far, but also important structure reflecting the geometry of the emitting region. Recent MHD simulations of Sgr A*'s...
Source: http://arxiv.org/abs/0705.0238v1
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48
Sep 20, 2013
09/13
by
John A. Tomsick; Richard Lingenfelter; Stephane Corbel; Andrea Goldwurm; Philip Kaaret
texts
eye 48
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We report on results from a 2003 February INTEGRAL observation of the black hole candidate (BHC) 4U 1630-47 and the high energy sources in the Norma Region of the Galaxy and on RXTE and radio observations of 4U 1630-47. To date, there have been 38 new or previously poorly studied sources found by INTEGRAL (the ``IGR'' sources), and 15 of the IGR sources are in the field of view of our observation. We detect 12 of the 15 sources, and we speculate that a subset of the IGR sources may be part of a...
Source: http://arxiv.org/abs/astro-ph/0404420v1
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76
Jul 20, 2013
07/13
by
Guillaume Belanger; Regis Terrier; Okkie De Jager; Andrea Goldwurm; Fulvio Melia
texts
eye 76
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We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which lasted a total of about three hours, was detected simultaneously by EPIC on XMM-Newton and the NICMOS near-infrared camera on the HST. Given the inherent difficulty in, and the lack of readily available methods for quantifying the probability of a periodic signal detected over only several cycles in a...
Source: http://arxiv.org/abs/astro-ph/0604337v2
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35
Sep 17, 2013
09/13
by
M. Falanga; J. Chenevez; A. Cumming; E. Kuulkers; G. Trap; A. Goldwurm
texts
eye 35
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Aims: The low persistent X-ray burster source SLX 1737-282 is classified as an ultra-compact binary candidate. We compare the data on SLX 1737-282 with the other similar objects and attempt to derive constraints on the physical processes responsible for the formation of intermediate long bursts. Methods: Up to now only three intermediate long bursts, all with duration between ~15-30 minutes, have been recorded for SLX 1737-282. The properties of two intermediate long X-ray bursts observed by...
Source: http://arxiv.org/abs/0711.0328v2
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41
Sep 21, 2013
09/13
by
M. Falanga; R. Farinelli; P. Goldoni; F. Frontera; A. Goldwurm; L. Stella
texts
eye 41
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We report the first detection with INTEGRAL of persistent hard X-ray emission (20 to 100 keV) from the Rapid Burster (MXB 1730-335), and describe its full spectrum from 3 to 100 keV. The source was detected on February/March 2003 during one of its recurrent outbursts. The source was clearly detected with a high signal to noise ratio during the single pointings and is well distinguished from the neighboring source GX 354-0. The 3 - 100 keV X-ray spectrum of the persistent emission is well...
Source: http://arxiv.org/abs/astro-ph/0407336v1
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38
Sep 22, 2013
09/13
by
Sergey Kuznetsov; Maurizio Falanga; Pere Blay; Andrea Goldwurm; Paolo Goldoni; Victor Reglero
texts
eye 38
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We present a first INTEGRAL observation of the 42s transient X-ray pulsar EXO 2030+375 with IBIS/ISGRI. The source was detected during Cyg X-1 observations in December 2002. We analyzed observations during the outburst period from 9 to 21 December 2002 with a total exposure time of ~770 kiloseconds. EXO 2030+375 was almost always detected during single ~30 minute exposures in the 18-45 energy bands. The source light curve shows the characteristic outburst shape observed in this source.
Source: http://arxiv.org/abs/astro-ph/0310225v1
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51
Sep 18, 2013
09/13
by
Marion Cadolle Bel; Marc Ribo; Jerome Rodriguez; Sylvain Chaty; Stephane Corbel; Andrea Goldwurm
texts
eye 51
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We report high-energy results obtained with INTEGRAL and Rossi-XTE on two microquasars: the persistent high-mass system Cygnus X-1 and the transient low-mass binary SWIFT J1753.5-0127. INTEGRAL observed Cygnus X-1 from 2002 to 2004: the spectral (5-1000 keV) properties of the source, seen at least in three distinct spectral states, show disc and corona changes. In 2003 June, a high-energy tail at several hundred keV in excess of the thermal Comptonization model was observed, suggesting the...
Source: http://arxiv.org/abs/astro-ph/0611217v1
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54
Sep 21, 2013
09/13
by
S. Mereghetti; D. I. Cremonesi; F. Haardt; T. Murakami; T. Belloni; A. Goldwurm
texts
eye 54
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GRS 1758-258 is one of the few persistent hard X-ray emitters (E>100 keV) in the Galaxy. Using the ASCA satellite, we have obtained the first detailed data on GRS 1758-258 in the 1-10 keV range, where previous observations were affected by confusion problems caused by the nearby strong source GX5-1. The spectrum is well described by a power law with photon index 1.7 without strong Fe emission lines. A prominent soft excess, as observed with ROSAT when the hard X-ray flux was in a lower...
Source: http://arxiv.org/abs/astro-ph/9609056v1
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47
Sep 18, 2013
09/13
by
F. Daigne; P. Goldoni; P. Ferrando; A. Goldwurm; A. Decourchelle; R. S. Warwick
texts
eye 47
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The XMM-Newton X-ray observatory performed a pointed observation of the bursting pulsar GRO J1744-28 in April 2001 for about 10 ks during a program devoted to the scan of the Galactic center region. After the discovery of this source by BATSE in December 1995 during a very active bursting phase, it has been in quiescence since April 1997. We present here the first detection of GRO J1744-28 in its quiescent state at a position which is consistent with previous high-energy positions (but not...
Source: http://arxiv.org/abs/astro-ph/0202209v1
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46
Sep 22, 2013
09/13
by
E. Brion; A. Goldwurm; P. Goldoni; P. Ferrando; F. Daigne; A. Decourchelle
texts
eye 46
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We report the results of XMM-Newton observations of Sgr A*, the radiative counterpart of the massive black hole at the nucleus of our Galaxy, performed in the frame of the guaranteed time survey program of the Galactic Center region. The discovery of bright X-ray flares from Sgr A* with Chandra in October 2000 have opened new perspectives to understand the processes at work in this object and in general in black holes accreting at low accretion rates. We report here the important results...
Source: http://arxiv.org/abs/astro-ph/0310150v1
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47
Sep 19, 2013
09/13
by
P. Goldoni; A. Goldwurm; P. Laurent; M. Casse'; J. Paul; C. Sarazin
texts
eye 47
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Cluster of galaxies are the largest concentrations of visible mass in the Universe and therefore a fundamental topic of cosmology and astrophysics. Recent radio, EUV, and X-ray observations suggest that clusters contain large populations of diffuse nonthermal relativistic and/or superthermal particles. These particles may be produced by acceleration in cluster merger shocks, AGNs, and/or supernovae in cluster galaxies. Models for the nonthermal populations in clusters indicate that they should...
Source: http://arxiv.org/abs/astro-ph/0102363v1
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34
Sep 18, 2013
09/13
by
Renaud Matthieu; Alexandra Gros; François Lebrun; Régis Terrier; Andréa Goldwurm; Steve Reynolds; Emrah Kalemci
texts
eye 34
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Context. In coded mask techniques, reconstructed sky images are pseudo-images: they are maps of the correlation between the image recorded on a detector and an array derived from the coded mask pattern. Aims. The INTEGRAL/IBIS telescope provides images where the flux of each detected source is given by the height of the local peak in the correlation map. As such, it cannot provide an estimate of the flux of an extended source. What is needed is intensity sky images giving the flux per solide...
Source: http://arxiv.org/abs/astro-ph/0606113v2
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44
Sep 22, 2013
09/13
by
L. Foschini; J. A. Tomsick; J. Rodriguez; R. Walter; A. Goldwurm; S. Corbel; P. Kaaret
texts
eye 44
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IGR J16320-4751 was re-discovered by IBIS/ISGRI on board INTEGRAL in early February 2003 during the observation of the black hole candidate 4U 1630-47 (PI Tomsick). This source, already observed by ASCA and BeppoSAX, belongs to the class of heavily absorbed objects (N_H > 10^23 cm^-2) that populate some arms of the Galaxy. Soon after the rediscovery by IBIS/ISGRI, the source was observed by XMM-Newton: the arcsec position found with XMM allowed ones to find the most likely infrared...
Source: http://arxiv.org/abs/astro-ph/0403479v2
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2.0
Jun 30, 2018
06/18
by
Maïca Clavel; R. Terrier; A. Goldwurm; M. R. Morris; G. Ponti; S. Soldi; G. Trap
texts
eye 2
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The supermassive black hole at the Galactic center, Sagittarius A*, has experienced periods of higher activity in the past. The reflection of these past outbursts is observed in the molecular material surrounding the black hole but reconstructing its precise lightcurve is difficult since the distribution of the clouds along the line of sight is poorly constrained. Using Chandra high-resolution data collected from 1999 to 2011 we studied both the 6.4 keV and the 4-8 keV emission of the region...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1410.5236
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47
Sep 17, 2013
09/13
by
D. Porquet; J. Rodriguez; S. Corbel; P. Goldoni; R. S. Warwick; A. Goldwurm; A. Decourchelle
texts
eye 47
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We report the results of an XMM-Newton observation of the persistent X-ray source 1E1743.1-2843, located in the Galactic Center (GC) direction. We determine the position of the source at alpha_J2000=17h46m21.0s, delta_J2000=-28deg43'44" (with an uncertainty of 1.5"), which is the most accurate to date, and will enable cross-identifications at other wavelengths. The source was bright during this observation (L_2-10keV ~ 2.7 x 10^36 d^2_10kpc erg/s for a power-law continuum), with no...
Source: http://arxiv.org/abs/astro-ph/0305489v1
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42
Sep 20, 2013
09/13
by
M. Falanga; D. Gotz; P. Goldoni; R. Farinelli; A. Goldwurm; S. Mereghetti; A. Bazzano; L. Stella
texts
eye 42
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We present for the first time a study of the 3-200 keV broad band spectra of the bursting atoll source 4U 1728-34 (GX 354-0) along its hardness intensity diagram. The analysis was done using the INTEGRAL public and Galactic Center deep exposure data ranging from February 2003 to October 2004. The spectra are well described by a thermal Comptonization model with an electron temperature from 35 keV to 3 keV and Thomson optical depth, tau_T, from 0.5 to 5 in a slab geometry. The source undergoes a...
Source: http://arxiv.org/abs/astro-ph/0607330v1
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42
Sep 19, 2013
09/13
by
J. Rodriguez; J. A. Tomsick; L. Foschini; R. Walter; A. Goldwurm; S. Corbel; P. Kaaret
texts
eye 42
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The hard X-ray sensitivity and arcminute position accuracy of the recently launched International Gamma-Ray Laboratory (INTEGRAL) has lead to the (re-)discovery of a class of heavily absorbed hard X-ray sources lying in the Galactic plane. We report on the analysis of an XMM observation of such a source IGR J16320-4751 = AX J1631.9-4752. Our analysis allowed us to obtain the most accurate X-ray position to date (Rodriguez et al. 2003), and to identify a likely infrared counterpart (Tomsick et...
Source: http://arxiv.org/abs/astro-ph/0304139v2
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5.0
Jun 30, 2018
06/18
by
Maïca Clavel; S. Soldi; R. Terrier; V. Tatischeff; G. Maurin; G. Ponti; A. Goldwurm; A. Decourchelle
texts
eye 5
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The origin of the iron fluorescent line at 6.4 keV from an extended region surrounding the Arches cluster is debated and the non-variability of this emission up to 2009 has favored the low-energy cosmic-ray origin over a possible irradiation by hard X-rays. By probing the variability of the Arches cloud non-thermal emission in the most recent years, including a deep observation in 2012, we intend to discriminate between the two competing scenarios. We perform a spectral fit of XMM-Newton...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1406.5727
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55
Sep 19, 2013
09/13
by
D. Porquet; N. Grosso; G. Belanger; A. Goldwurm; F. Yusef-Zadeh; R. S. Warwick; P. Predehl
texts
eye 55
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We present the XMM-Newton observations obtained during four revolutions in Spring and Summer 2004 of CXOGC J174540.0-290031, a moderately bright transient X-ray source, located at only 2.9" from SgrA*. We report the discovery of sharp and deep X-ray eclipses, with a period of 27,961+/-5 s and a duration of about 1,100+/-100 s, observed during the two consecutive XMM revolutions from August 31 to September 2. No deep eclipses were present during the two consecutive XMM revolutions from...
Source: http://arxiv.org/abs/astro-ph/0507283v1
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50
Sep 19, 2013
09/13
by
A. Goldwurm; E. Brion; P. Goldoni; P. Ferrando; F. Daigne; A. Decourchelle; R. S. Warwick; P. Predehl
texts
eye 50
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The compact radio source Sgr A*, believed to be the counterpart of the massive black hole at the Galactic nucleus, was observed to undergo rapid and intense flaring activity in X-rays with Chandra in October 2000. We report here the detection with XMM-Newton EPIC cameras of the early phase of a similar X-ray flare from this source, which occurred on 2001 September 4. The source 2-10 keV luminosity increased by a factor ~ 20 to reach a level of 4 10$^{34}$ erg s$^{-1}$ in a time interval of...
Source: http://arxiv.org/abs/astro-ph/0303583v1
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39
Sep 22, 2013
09/13
by
A. Goldwurm; D. Israel; P. Goldoni; P. Ferrando; A. Decourchelle; I. F. Mirabel; R. S. Warwick
texts
eye 39
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The XMM-Newton X-ray observatory pointed the galactic black hole candidate and microquasar GRS 1758-258 in September 2000 for about 10 ks during a program devoted to the scan of the Galactic Center regions. Preliminary results from EPIC MOS camera data are presented here. The data indicate that the source underwent a state transition from its standard low-hard state to an intermediate state. For the first time in this source the ultra-soft component of the accretion disk, which black hole...
Source: http://arxiv.org/abs/astro-ph/0106310v1
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43
Sep 22, 2013
09/13
by
M. Falanga; L. Kuiper; J. Poutanen; D. K. Galloway; E. Bozzo; A. Goldwurm; W. Hermsen; L. Stella
texts
eye 43
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During the last 10 years, INTEGRAL made a unique contribution to the study of accreting millisecond X-ray pulsars (AMXPs), discovering three of the 14 sources now known of this class. Besides increasing the number of known AMXPs, INTEGRAL also carried out observations of these objects above 20 keV, substantially advancing our understanding of their behaviour. We present here a review of all the AMXPs observed with INTEGRAL and discuss the physical interpretation of their behaviour in the X-ray...
Source: http://arxiv.org/abs/1302.2843v1
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39
Sep 21, 2013
09/13
by
Guillaume Belanger; Andrea Goldwurm; Fulvio Melia; Farah Yusef-Zadeh; Philippe Ferrando; Delphine Porquet; Nicolas Grosso; Robert Warwick
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Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms in this supermassive black hole located at the center of our Galaxy. Several X-ray flares with varying durations and spectral features have already been observed from this object. Here we present the results of two long XMM-Newton observations of the Galactic nucleus carried out in 2004, for a total...
Source: http://arxiv.org/abs/astro-ph/0508412v1
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58
Sep 22, 2013
09/13
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D. Porquet; P. Predehl; B. Aschenbach; N. Grosso; A. Goldwurm; P. Goldoni; R. S. Warwick; A. Decourchelle
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We report the high S/N observation on October 3, 2002 with XMM-Newton of the brightest X-ray flare detected so far from SgrA* with a duration shorter than one hour (~ 2.7 ks). The light curve is almost symmetrical with respect to the peak flare, and no significant difference between the soft and hard X-ray range is detected. The overall flare spectrum is well represented by an absorbed power-law with a soft photon spectral index of Gamma=2.5+/-0.3, and a peak 2-10 keV luminosity of 3.6...
Source: http://arxiv.org/abs/astro-ph/0307110v1
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53
Sep 17, 2013
09/13
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A. Goldwurm; E. Brion; P. Goldoni; P. Ferrando; F. Daigne; A. Decourchelle; R. S. Warwick; P. Predehl
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Sgr A*, the compact radio source, believed to be the counterpart of the massive black hole at the galactic nucleus, was observed to undergo rapid and intense flaring activity in X-rays with Chandra in October 2000. We report here the detection with XMM-Newton EPIC cameras of the early phase of a similar X-ray flare from this source, which occurred on September 4, 2001. The source 2-10 keV luminosity increased by a factor about 20 to reach a level of 4 10^{34} erg s^{-1} in a time interval of...
Source: http://arxiv.org/abs/astro-ph/0207620v2
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58
Sep 21, 2013
09/13
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A. Gros; A. Goldwurm; M. Cadolle-Bel; P. Goldoni; J. Rodriguez; L. Foschini; M. Del Santo; P. Blay
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The imager on board INTEGRAL (IBIS) presently provides the most detailed sky images ever obtained at energies above 30 keV. The telescope is based on a coded aperture imaging system which allows to obtain sky images in a large field of view 29deg x 29deg with an angular resolution of 12'. The System Point Spread Function of the telescope and its detailed characteristics are here described along with the specific analysis algorithms used to derive the accurate point-like source locations. The...
Source: http://arxiv.org/abs/astro-ph/0311176v1
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61
Sep 21, 2013
09/13
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A. Goldwurm; P. David; L. Foschini; A. Gros; P. Laurent; A. Sauvageon; A. J. Bird; L. Lerusse; N. Produit
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The gamma-ray astronomical observatory INTEGRAL, succesfully launched on 17th October 2002, carries two large gamma-ray telescopes. One of them is the coded-mask imaging gamma-ray telescope onboard the INTEGRAL satellite (IBIS) which provides high-resolution (~ 12') sky images of 29deg x 29deg in the energy range from 15 keV to 10 MeV with typical on-axis sensitivity of ~ 1 mCrab at 100 keV (3 sigma, 10E6 s exposure). We report here the general description of the IBIS coded-mask imaging system...
Source: http://arxiv.org/abs/astro-ph/0311172v1
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51
Sep 21, 2013
09/13
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Guillaume Belanger; Andrea Goldwurm; Matthieu Renaud; Regis Terrier; Fulvio Melia; Niels Lund; Jacques Paul; Gerry Skinner; Farah Yusef-Zadeh
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The Ibis/Isgri imager on Integral detected for the first time a hard X-ray source, IGR J17456-2901, located within 1' of Sgr A* over the energy range 20-100 keV. Here we present the results of a detailed analysis of ~7 Ms of Integral observations of the GC. With an effective exposure of 4.7 Ms we have obtained more stringent positional constraints on this HE source and constructed its spectrum in the range 20-400 keV. Furthermore, by combining the Isgri spectrum with the total X-ray spectrum...
Source: http://arxiv.org/abs/astro-ph/0508128v1
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51
Jul 19, 2013
07/13
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R. Terrier; G. Ponti; G. Belanger; A. Decourchelle; V. Tatischeff; A. Goldwurm; G. Trap; M. R. Morris; R. Warwick
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The centre of our Galaxy harbours a 4 million solar mass black hole that is unusually quiet: its present X-ray luminosity is more than 10 orders of magnitude less than its Eddington luminosity. The observation of iron fluorescence and hard X-ray emission from some of the massive molecular clouds surrounding the Galactic Centre has been interpreted as an echo of a past flare. Alternatively, low-energy cosmic rays propagating inside the clouds might account for the observed emission, through...
Source: http://arxiv.org/abs/1005.4807v1
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Sep 22, 2013
09/13
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G. Trap; M. Falanga; A. Goldwurm; E. Bozzo; R. Terrier; P. Ferrando; D. Porquet; N. Grosso; M. Sakano
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The neutron star low-mass X-ray binary GRS 1741.9-2853 is a known type-I burster of the Galactic Center. It is transient, faint, and located in a very crowded region, only 10 arcmin from the supermassive black hole Sgr A*. Therefore, its bursting behavior has been poorly studied so far. In particular, its persistent emission has rarely been detected between consecutive bursts, due to lack of sensitivity or confusion. This is what made GRS 1741.9-2853 one of the nine "burst-only...
Source: http://arxiv.org/abs/0906.3633v1
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Sep 20, 2013
09/13
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Regis Terrier; Francois Lebrun; Guillaume Belanger; Andrea Goldwurm; Andrew W. Strong; Volker Schoenfelder; Laurent Bouchet; Jean-Pierre Roques; Arvind Parmar
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The nature of the soft gamma-ray (20-200 keV) Galactic emission has been a matter of debate for a long time. Previous experiments have tried to separate the point source contribution from the real interstellar emission, but with a rather poor spatial resolution, they concluded that the interstellar emission could be a large fraction of the total Galactic emission. INTEGRAL, having both high resolution and high sensitivity, is well suited to reassess more precisely this problem. Using the...
Source: http://arxiv.org/abs/astro-ph/0405207v1
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Sep 23, 2013
09/13
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M. Falanga; L. Kuiper; J. Poutanen; D. K. Galloway; E. W. Bonning; E. Bozzo; A. Goldwurm; W. Hermsen; L. Stella
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IGR J17511-3057 is the second X-ray transient accreting millisecond pulsar discovered by INTEGRAL. It was in outburst for about a month from September 13, 2009. The broad-band average spectrum is well described by thermal Comptonization with an electron temperature of kT_e ~ 25 keV, soft seed photons of kT_bb ~ 0.6 keV, and Thomson optical depth \tau_T ~ 2 in a slab geometry. During the outburst the spectrum stays remarkably stable with plasma and soft seed photon temperatures and scattering...
Source: http://arxiv.org/abs/1012.0229v1